WASHINGTON -- The Supreme Court made life a bit tougher for government whistleblowers yesterday, saying the First Amendment doesn't protect public employees who disclose waste and fraud as part of their jobs.

In a victory for the Bush administration, the justices said the government's interest in effectively managing operations outweighs the interests that protect employee speech, even in cases where employees may be reporting inefficiencies or wrongdoing.

Critics predicted that the impact on public employees -- about 20 million at the local, state and federal levels -- would be sweeping, from silencing police officers who fear retribution for reporting department corruption, to subduing workers who want to reveal problems with government hurricane preparedness or terrorist-related security.

Supporters said it will protect governments from lawsuits filed by disgruntled workers pretending to be legitimate whistleblowers.

The 5-4 ruling was perhaps the clearest sign yet of the Supreme Court's shift with the departure of moderate Justice Sandra Day O'Connor and the arrival of Justice Samuel Alito, who cast the deciding vote.

A year ago, O'Connor authored a 5-4 decision that encouraged whistleblowers to report sex discrimination in schools. The current case was argued in October but not resolved before her retirement in late January.

A new argument session was held in March with Alito on the bench. He joined the court's other conservatives in yesterday's decision, which split along traditional conservative-liberal lines.

Exposing government misconduct is important, Justice Anthony M. Kennedy wrote for the majority. "We reject, however, the notion that the First Amendment shields from discipline the expressions employees make pursuant to their professional duties," Kennedy said.

The ruling overturned an appeals court decision that said Los Angeles County prosecutor Richard Ceballos was constitutionally protected when he wrote a memo questioning whether a county sheriff's deputy had lied in a search warrant affidavit. Ceballos had filed a lawsuit claiming he was demoted and denied a promotion for trying to expose the lie.

Kennedy said that if the superiors thought the memo was inflammatory, they had the authority to punish him.

"Official communications have official consequences, creating a need for substantive consistency and clarity. Supervisors must ensure that their employees' official communications are accurate, demonstrate sound judgment and promote the employer's mission," Kennedy wrote.

Stephen Kohn, chairman of the National Whistleblower Center, said: "The ruling is a victory for every crooked politician in the United States."

Justice David H. Souter's lengthy dissent sounded like it might have been the majority opinion if O'Connor were still on the court. "Private and public interests in addressing official wrongdoing and threats to health and safety can outweigh the government's stake in the efficient implementation of policy," he wrote.

Souter was joined by Justices John Paul Stevens and Ruth Bader Ginsburg. Justice Stephen Breyer also supported Ceballos, but on different grounds.

The ruling upheld the position of the Bush administration, which had joined the district attorney's office in opposing absolute free-speech rights for whistleblowers. President Bush's two nominees, Alito and Chief Justice John Roberts, signed on to Kennedy's opinion but did not write separately.

Employment attorney Dan Westman said Kennedy's ruling frees government managers to take necessary personnel actions, like negative performance reviews or demotions, without fear of frivolous lawsuits.

"I don't think he's unleashed a wave of terminations," Westman said.

The court's decision immediately prompted calls for Congress to strengthen protections for workers.

Kennedy said government workers "retain the prospect of constitutional protection for their contributions to the civic discourse." They do not, Kennedy said, have "a right to perform their jobs however they see fit."